Question about Cortisporin (topical neomycin)

[jakesaw]

I apologize this post is not in relation to residency, but I have a question I thought a future ENT might know (I'm an MSIII interested in IM or FP).

I was recently prescribed Cortisporin (neomycin, polymyxin b, hydrocortisone) for otitis externa. When I realized the Rx was an aminoglycoside I immediately asked the pharmacist about ototoxicity. She had no clue, thought I was crazy and just responded that it's used all the time for ear infections.

Is it correct that aminoglycoside-induced ototoxicity from topical drops can only occur when there is a perforation of the tympanic membrane (and a really stupid question, how would I know if I had one since I can't look in my own ear?)? Or is ototoxicity a real possibility when used as prescribed?

The prescribing info clearly documents ototoxicity. I've decided, overcautiously or not, to stop the cortisporin. Am I just being paranoid?

How about floroquinolones? I thought they were supposed to be non-ototoxic and that Floxin Otic (ofloxacin) can even be used with a perforated TM, yet I've come across claims they too can be ototoxic.

I was supposed to be a rock star before deciding on medicine, so my hearing is very important to me.

Does anyone have thoughts on this? Thanks.

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[neutropeniaboy]

Don't worry about it.

There was a recent consensus statement published by the Head and Neck Academy in March of 2004 on the use of topical antibiotics in the treatment of "ear disease."

The statement basically says that aminoglycoside preparations should not be used if quinolone agents are readily and easily acquired. Having made that statement, they note that the use of aminoglycoside preparations have a low, but experimentally (in animals) and clinically notable, incidence of ototoxicity in the open middle ear. Quinolones have not been noted to cause ototoxicity in normally applied concentrations. I think in a later supplement, there were several good studies that show quinolones are no more effective than Cortisporin.

Should you have been prescribed a quinolone? I think I would have prescribed it. However, I wouldn't raise an eyebrow at the physician who prescribed it. I try not prescribe it anymore because I've had too many people develop allergic/contact reactions to neomycin (mostly African Americans). I will readily prescribe it, however, if people can't afford Floxin, Cipro HC, or Ciprodex.

On a related note, you should consider prescribing VoSol (acetic acid). In eczematous otitis or mild otitis externa, I find that it works pretty well.

I apologize this post is not in relation to residency, but I have a question I thought a future ENT might know (I'm an MSIII interested in IM or FP).

I was recently prescribed Cortisporin (neomycin, polymyxin b, hydrocortisone) for otitis externa. When I realized the Rx was an aminoglycoside I immediately asked the pharmacist about ototoxicity. She had no clue, thought I was crazy and just responded that it's used all the time for ear infections.

Is it correct that aminoglycoside-induced ototoxicity from topical drops can only occur when there is a perforation of the tympanic membrane (and a really stupid question, how would I know if I had one since I can't look in my own ear?)? Or is ototoxicity a real possibility when used as prescribed?

The prescribing info clearly documents ototoxicity. I've decided, overcautiously or not, to stop the cortisporin. Am I just being paranoid?

How about floroquinolones? I thought they were supposed to be non-ototoxic and that Floxin Otic (ofloxacin) can even be used with a perforated TM, yet I've come across claims they too can be ototoxic.

I was supposed to be a rock star before deciding on medicine, so my hearing is very important to me.

Does anyone have thoughts on this? Thanks.

 

[jakesaw]

Thanks--I'll give the VoSol a try.

 

[jakesaw]

Neutropeniaboy, If you happen to read this I have a question regarding the VoSol--- what is the propanediol component? Any potential toxicity? I know I'm be overly cautious but I really dislike the fact I was putting neomycin into my ear).

Also, can mild-moderate otitis externa be self-limiting? Thanks again.

 

[TheThroat]

NPboy already answered this more succinctly than I could, but, more for historical reasons than anything else, we still use cortisporin pretty frequently. It works well and the incidence of ototoxicity, even with a perf, is really low. I would use it for external otitis, mainly bc/ its so cheap compared to the alternatives.

 

[jakesaw]

Thanks!

 

[sdn1977]

I'll try to add some reassurance. I'm a pharmacist who was a student when gentamicin was a "new" drug...so I remember the neomycin days. I'll apologize for my colleague-if she didn't know the answer, she should have offered to find out. Here's why we still use cortisporin: neomycin is poorly abosorbed-only 97% of an oral dose is absorbed (which is why it is useful as a bowel prep-altho rarely used today). It is even less absorbed topically or via mucous membranes. A total daily oral intake of 10g for 3 days yields a blood concentration below levels associated with toxicity. Cortisporin has 3.5mg/ml of neomycin & there are approx 10 drops per ml - you'd have to flood your ear continuously to yield a sufficiently high blood level to worry about! We use it because it works - and the less we use the new antibiotics, the less we induce resistance. Fluoroquinolones should be reserved for those folks who don't respond to the older ones or who have medical justification for the use of them. Cortisporin is available as a solution & suspension - solutions are used when the risk of perforation of the eardrum is high. Floxin is a solution, but we need to save it for those purposes when cortisporin won't work. Cipro is not available by itself as an otic preparation (but, the ophthalamic drop will work just fine in the ear). Cipro ear preparations have hydrocortisone or dexamethasone and are very expensive - approx $80 per Rx. The real negative to cortisporin as a "good" drug is neomycin is very good at inducing hypersensitive reactions - 6-8% and unfortunately this hypersensitivity cross reacts with other aminoglycosides, which is a risk for those patients with chronic otitic or ophthalamic (yes...its available as an eye drop too!) infections. Fortunately, very few people are treated multiple times and often if topical therapy doesn't work, the choice is made to go with oral therapy and a fluoroquinolone. (Ophthalmic infections are more frequent - thus, we use cortisporin here less - more sulfonamides and fluoroquinolones). While at work I checked the price for those 2 choices without insurance in CA - $30 for a bottle of cortisporin & $68 for cipro - does that influence your choice????

 

[alanr1]

Hello,
Well antibiotics are very necessary part of our life .It saves us from various disease .I am thankful to you giving lots of information regarding the ophthalamic .So very big number of antibiotics are available now for various disease .Gentamicin dosage is the also the best for removal of diseases. But I want to know in detail about the working of these.